CASE REPORT
adenosine paroxysmal supraventricular tachycardia
Adenosine in the Treatment of Paroxysmal Supraventricular Tachycardia in Children From the Divisions of Pediatric Intensive Care* and Pediatric Cardiology,t Childrens Hospital Los Angeles; and Department of Pediatrics, University of Southern California School of Medicine, Los Angeles.¢
Gerardo Reyes, MD* Robert Stanton, MD t Antonio G Galvis, MD*
Received for publication November 4, 1991. Revision received March 25, 1992. Accepted for publication June 4, 1992.
Intravenous bolus adenosine was given to four pediatric patients aged 1 month to 8 years who had paroxysmal supraventricuIar tachycardia that had not responded to conventional medical therapy. Adenosine (one to three doses) was successful in converting the arrhythmia to normal sinus rhythm in all four cases, and no side effects of the drug were noted. [Reyes G, Stanton R, Galvis AG: Adenosine in the treatment of paroxysmal supraventricular tachycardia in children. Ann EmergMefl December 1992;21:1499-1501 .] INTRODUOTION Between one in 250 and one in 1,000 children experience paroxysmal supraventricular tachycardia (PSVT). When the patient is hemodynamically stable, this arrhythmia may be managed by conventional medical techniques: providing supplemental oxygen; performing vagal maneuvers; and initiating IV therapy with digitalis, verapamil, propranolol, edrophonium, or neosynephrine. When the arrhythmia persists or when the patient is hemodynamically unstable, synchronized electrical cardioversion is performed. Although medications such as verapamil are effective for PSVT, they have significant hemodynamic side effects and should be used only with extreme caution in children younger than i year old.1 Many studies have documented the effectiveness of adenosine in treating PSVT in adults; however, few studies have been performed in children. This report describes our experience with this new antiarrhythmic drug in treating PSVT in four children. CASE R E P O R T S
Case I An 8-year-old girl was brought to the emergency department of the referring hospital with a three-day history of nausea, vomiting, anorexia, and intermittent chest palpitations lasting several hours. An ECG showed narrow complex tachycardia at a rate of 235. After vagal maneuvers and two doses of verapamil IV (1 mg each dose) had been tried without success, the patient was transferred to our institution. On admission she had a heart rate of 250 and blood pressure of 100/60 rmn Hg. Adenosine 0.1 mg/kg IV bolus was given, and her arrhythmia converted to normal sinus rhythm. Digoxin therapy was begun, and she was discharged home 48 hours later.
DECEMBER1992
21:12
ANNALS OF EMERGENCY MEDIClNE
1499/119
ADENOSINE Reyes, Stanton & Galvis
C a s e 2 A 1-month-old boy was brought to the El) of a referring hospital for evaluation and treatment of lethargy and cold extremities. An ECG revealed n a r r o w complex tachycardia at a rate of 245. Ice packs were applied to the patient's face, and carotid sinus massage was performed; in addition, verapamil 0.075 mg/kg IV and phenylephrine 0.1 mg/kg IV were given, but the a r r h y t h m i a did not resolve. After a telephone consultation with the intensive care physicians of our institution, the patient was given adenosine 0.1 mg/kg IV, and the a r r h y t h m i a p r o m p t l y converted to normal sinus rhythm. The patient then was t r a n s f e r r e d to our institution. The next day, during placement of an internal jugular venous catheter, the patient had another episode of PSVT that converted to n o r m a l sinus r h y t h m r a p i d l y after administration of adenosine 0.1 mg/kg IV. C a s e 3 During percutaneous balloon p u l m o n a r y valvotomy, a 7-year-old girl developed a n a r r o w complex tachycardia at a rate of 240; blood pressure remained stable at 100/50 mm Hg. She was given adenosine 0.1 mg/kg IV, and the a r r h y t h m i a converted to normal sinus r h y t h m immediately (Figure 1). C a s e 4 An 8-year-old boy was brought to the ED of a referring hospital with a new onset of chest pain and palpitations. An ECG showed n a r r o w complex t a c h y c a r d i a at a rate of 240. When vagal maneuvers followed by two doses of adenosine 0.1 mg/kg IV peripherally failed to control the a r r h y t h m i a , the patient was t r a n s f e r r e d to the ICU. On arrival he was alert and cooperative, with blood pressure of 110/65 mm Hg, h e a r t rate of 220, strong p e r i p h e r a l pulses, and normal r e s p i r a t o r y effort. A t h i r d dose of adenosine 0.2 mg/kg IV was given through a p e r i p h e r a l catheter with immediate conversion of the a r r h y t h m i a to normal sinus rhythm (Figure 2). DISCUSSION
Adenosine is an endogenous purine nucleoside whose electrophysiologic effects on the cardiac conduction system were first described by D r u r y and Szent-Gyorgyi in 1929. 2 They showed that IV adenosine in dogs slowed sinus h e a r t rate and produced temporary atrioventricular block. Only during the past few years, however, have extensive studies of the Figure 1.
electrophysiologic effects of adenosine in human beings shown this agent to be effective in relieving PSVT. Adenosine exerts both negative chronotropic and dromotropic effects on the h e a r t through extracellular adenosine A 1 receptors. In the sinoatrial node, adenosine depresses the activity of the p r i m a r y pacemaker cells by causing hyperpolarization of the cell membrane, which results in a decrease in the slope of phase 4 depolarization. By a similar bioelectrical mechanism, adenosine blocks conduction in the nodal region of the atrioventricular node; it is by this latter mechanism that adenosine blocks the reentrant circuit necessary for sustaining the tachyarrhythmia.3-5 Adenosine has a plasma half-life of less than ten seconds, thus limiting the duration of its pharmacologic actions and side effects. It is taken up by erythrocytes and vascular endothelial cells and metabolized to inosine, adenosine monophosphate, and hypoxanthine-xanthine. Because of its very short half-life, adenosine should be given as a r a p i d IV bolus, p r e f e r a b l y through a central venous catheter. 6 Side effects associated with the use of adenosine are limited in scope and duration. Sinus b r a d y c a r d i a , long sinus node pauses, hypotension, flushing, and dyspnea are the most common side effects; all are of short duration, lasting less than one minute. 7 No side effects were noted in our patients. Two other reports have been published in the use of adenosine in the treatment of PSVT in children. Clarke et al 8 used the drug successfully in four patients aged 7 days to 10 years, and Ros et al 9 used it successfully in a 16-year-old girl and a 24-day-old infant with PSVT. In a recent review on the treatment of SVT in children, Till and Shinebourne 1° recommended the use of adenosine if vagal maneuvers have failed. Adenosine has also been found to be useful during electrophysiologic studies to evaluate i n t r a - a t r i a l tachycardia. In one group of 25 c h i l d r e n , adenosine was used to b l o c k atrioventricular conduction temporarily to facilitate the diagnosis of the a r r h y t h m i a mechanism.IX
Figure 2. ECG of an 8-year-old boy shows conversion of PSVT to normal sinus rhythm after third (two O.2-mg/kg doses and one 0.2-mg/kg dose) IV bolus of adenosine (arrow).
ECG of a 7-year-old girl shows conversion of PSVT to normal sinus rhythm with IV bolus of O.1 mg/kg adenosine (arrow). Adenosine: O.1 MG/KG IV
| :
I20/1500
Po,|i, i
17YRF
ANNALSOF EMERGENCYMEDICINE 21:12 DECEMBER1992
ADENOSINE
Reyes, Stanton & Galvis
Our experience and those r e p o r t e d by others support the use of adenosine in the treatment of PSVT in children. The drug is safe and effective, has a r a p i d onset of action, and lacks the hemodynamic side effects of verapamil or p r o p r a nolol or the dangers and discomforts of electrical cardioversion. It is ideal for use in children less than i year old because of its limited hemodynamic side effects. We recommend an initial dose of 0.1 mg/kg to be given as a r a p i d IV bolus; the dose can be repeated several times and increased to 0.3 mg/kg if needed. This is possible because of its short half-life, which precludes toxic side effects from drug accumulation.
REFERENCES 1. Ludomirsky A, 6arson A: Supraventrieular tachycardia, in 6illette PC, Garson A (eds): Pediatric Arrhythmias: Electrophysiology and Pacing, ed 1. Philadelphia, WB Sa unders, 1990, p 380-426. 2. Drury AN, Szent-6yorgyi A: The physiological activity of adenosine compounds with especial reference te their action upon the mammalian heart. J Physio11929;68:213-237. 3. West 6A: Actions of adenosine on the sinus node. Prog Clin BiolRes 1987;230:97-108. 4. Belardinelli L: Modulation of atrioventricular transmission by adenosine. Prog Clin Biol Res 1987;230:109-118. 5. DiMarco JP: Adenosine and supraventricular tachycardia. Prog Clin Biol Res 1987;230:271-282. 6. Moak JP: Pharmacology and electrcphysiology of antiarrhythmic drugs, in Gillette PC, Garscn A (eds): Pediatric Arrhythmias: Electrophysiology and Pacing, ed 1. Philadelphia, WB Saunders, 1990, p 37-117.
SUMMARY
Adenosine should be considered the first drug of choice in the treatment of PSVT in infants and children. Adenosine should also be considered in patients who are hemodynamically unstable, because of its fast onset of action. However, controlled, prospective studies should be performed to establish the true efficacy and safety of adenosine in the treatment of PSVT in the pediatric population as compared with digitalis, verapamil, and propanolol.
7. DiMarco JP, Sellers TD, Lerman BB, et al: Diagnostic and therapeutic use of adenosine in patients with supraventricular tachyarrhythmias. JAm Coil Cardiol 1985;8:417-425. 8. Clarke B, Till J, Roland E, et al: Rapid and safe termination of supraventricular tachycardia in children by adenosine. Lancet 1987;1:299-301. 9. Ros SP, Fisher EA, Bell TJ: Adenosine in the emergency treatment of supraventricular tachycardia. Pediatr Emerg Care 1991;7:222-223. 10. Till JA, Shinebourne EA: Supraventricular tachycardia: Diagnosis and current acute management. Arch Dis Child 1991;66:647-652. 11. Overholt ED, Rheuban KS, 6utgesell HP, et al: Usefulness of adenosine for arrhythmias in infants and children. Am J Cardio11988;61:336-340. Address for reprints: Antonio G Galvis, MD Childrens Hospital Los Angeles Division of Pediatric Intensive Care 4650 Sunset Boulevard Los Angeles, California 90027
DECEMBER1992
21:12
ANNALS OF EMERGENCY MEDICINE
1501/I21
adenosine paroxysmal supraventricular tachycardia
Adenosine in the Treatment of Paroxysmal Supraventricular Tachycardia in Children From the Divisions of Pediatric Intensive Care* and Pediatric Cardiology,t Childrens Hospital Los Angeles; and Department of Pediatrics, University of Southern California School of Medicine, Los Angeles.¢
Gerardo Reyes, MD* Robert Stanton, MD t Antonio G Galvis, MD*
Received for publication November 4, 1991. Revision received March 25, 1992. Accepted for publication June 4, 1992.
Intravenous bolus adenosine was given to four pediatric patients aged 1 month to 8 years who had paroxysmal supraventricuIar tachycardia that had not responded to conventional medical therapy. Adenosine (one to three doses) was successful in converting the arrhythmia to normal sinus rhythm in all four cases, and no side effects of the drug were noted. [Reyes G, Stanton R, Galvis AG: Adenosine in the treatment of paroxysmal supraventricular tachycardia in children. Ann EmergMefl December 1992;21:1499-1501 .] INTRODUOTION Between one in 250 and one in 1,000 children experience paroxysmal supraventricular tachycardia (PSVT). When the patient is hemodynamically stable, this arrhythmia may be managed by conventional medical techniques: providing supplemental oxygen; performing vagal maneuvers; and initiating IV therapy with digitalis, verapamil, propranolol, edrophonium, or neosynephrine. When the arrhythmia persists or when the patient is hemodynamically unstable, synchronized electrical cardioversion is performed. Although medications such as verapamil are effective for PSVT, they have significant hemodynamic side effects and should be used only with extreme caution in children younger than i year old.1 Many studies have documented the effectiveness of adenosine in treating PSVT in adults; however, few studies have been performed in children. This report describes our experience with this new antiarrhythmic drug in treating PSVT in four children. CASE R E P O R T S
Case I An 8-year-old girl was brought to the emergency department of the referring hospital with a three-day history of nausea, vomiting, anorexia, and intermittent chest palpitations lasting several hours. An ECG showed narrow complex tachycardia at a rate of 235. After vagal maneuvers and two doses of verapamil IV (1 mg each dose) had been tried without success, the patient was transferred to our institution. On admission she had a heart rate of 250 and blood pressure of 100/60 rmn Hg. Adenosine 0.1 mg/kg IV bolus was given, and her arrhythmia converted to normal sinus rhythm. Digoxin therapy was begun, and she was discharged home 48 hours later.
DECEMBER1992
21:12
ANNALS OF EMERGENCY MEDIClNE
1499/119
ADENOSINE Reyes, Stanton & Galvis
C a s e 2 A 1-month-old boy was brought to the El) of a referring hospital for evaluation and treatment of lethargy and cold extremities. An ECG revealed n a r r o w complex tachycardia at a rate of 245. Ice packs were applied to the patient's face, and carotid sinus massage was performed; in addition, verapamil 0.075 mg/kg IV and phenylephrine 0.1 mg/kg IV were given, but the a r r h y t h m i a did not resolve. After a telephone consultation with the intensive care physicians of our institution, the patient was given adenosine 0.1 mg/kg IV, and the a r r h y t h m i a p r o m p t l y converted to normal sinus rhythm. The patient then was t r a n s f e r r e d to our institution. The next day, during placement of an internal jugular venous catheter, the patient had another episode of PSVT that converted to n o r m a l sinus r h y t h m r a p i d l y after administration of adenosine 0.1 mg/kg IV. C a s e 3 During percutaneous balloon p u l m o n a r y valvotomy, a 7-year-old girl developed a n a r r o w complex tachycardia at a rate of 240; blood pressure remained stable at 100/50 mm Hg. She was given adenosine 0.1 mg/kg IV, and the a r r h y t h m i a converted to normal sinus r h y t h m immediately (Figure 1). C a s e 4 An 8-year-old boy was brought to the ED of a referring hospital with a new onset of chest pain and palpitations. An ECG showed n a r r o w complex t a c h y c a r d i a at a rate of 240. When vagal maneuvers followed by two doses of adenosine 0.1 mg/kg IV peripherally failed to control the a r r h y t h m i a , the patient was t r a n s f e r r e d to the ICU. On arrival he was alert and cooperative, with blood pressure of 110/65 mm Hg, h e a r t rate of 220, strong p e r i p h e r a l pulses, and normal r e s p i r a t o r y effort. A t h i r d dose of adenosine 0.2 mg/kg IV was given through a p e r i p h e r a l catheter with immediate conversion of the a r r h y t h m i a to normal sinus rhythm (Figure 2). DISCUSSION
Adenosine is an endogenous purine nucleoside whose electrophysiologic effects on the cardiac conduction system were first described by D r u r y and Szent-Gyorgyi in 1929. 2 They showed that IV adenosine in dogs slowed sinus h e a r t rate and produced temporary atrioventricular block. Only during the past few years, however, have extensive studies of the Figure 1.
electrophysiologic effects of adenosine in human beings shown this agent to be effective in relieving PSVT. Adenosine exerts both negative chronotropic and dromotropic effects on the h e a r t through extracellular adenosine A 1 receptors. In the sinoatrial node, adenosine depresses the activity of the p r i m a r y pacemaker cells by causing hyperpolarization of the cell membrane, which results in a decrease in the slope of phase 4 depolarization. By a similar bioelectrical mechanism, adenosine blocks conduction in the nodal region of the atrioventricular node; it is by this latter mechanism that adenosine blocks the reentrant circuit necessary for sustaining the tachyarrhythmia.3-5 Adenosine has a plasma half-life of less than ten seconds, thus limiting the duration of its pharmacologic actions and side effects. It is taken up by erythrocytes and vascular endothelial cells and metabolized to inosine, adenosine monophosphate, and hypoxanthine-xanthine. Because of its very short half-life, adenosine should be given as a r a p i d IV bolus, p r e f e r a b l y through a central venous catheter. 6 Side effects associated with the use of adenosine are limited in scope and duration. Sinus b r a d y c a r d i a , long sinus node pauses, hypotension, flushing, and dyspnea are the most common side effects; all are of short duration, lasting less than one minute. 7 No side effects were noted in our patients. Two other reports have been published in the use of adenosine in the treatment of PSVT in children. Clarke et al 8 used the drug successfully in four patients aged 7 days to 10 years, and Ros et al 9 used it successfully in a 16-year-old girl and a 24-day-old infant with PSVT. In a recent review on the treatment of SVT in children, Till and Shinebourne 1° recommended the use of adenosine if vagal maneuvers have failed. Adenosine has also been found to be useful during electrophysiologic studies to evaluate i n t r a - a t r i a l tachycardia. In one group of 25 c h i l d r e n , adenosine was used to b l o c k atrioventricular conduction temporarily to facilitate the diagnosis of the a r r h y t h m i a mechanism.IX
Figure 2. ECG of an 8-year-old boy shows conversion of PSVT to normal sinus rhythm after third (two O.2-mg/kg doses and one 0.2-mg/kg dose) IV bolus of adenosine (arrow).
ECG of a 7-year-old girl shows conversion of PSVT to normal sinus rhythm with IV bolus of O.1 mg/kg adenosine (arrow). Adenosine: O.1 MG/KG IV
| :
I20/1500
Po,|i, i
17YRF
ANNALSOF EMERGENCYMEDICINE 21:12 DECEMBER1992
ADENOSINE
Reyes, Stanton & Galvis
Our experience and those r e p o r t e d by others support the use of adenosine in the treatment of PSVT in children. The drug is safe and effective, has a r a p i d onset of action, and lacks the hemodynamic side effects of verapamil or p r o p r a nolol or the dangers and discomforts of electrical cardioversion. It is ideal for use in children less than i year old because of its limited hemodynamic side effects. We recommend an initial dose of 0.1 mg/kg to be given as a r a p i d IV bolus; the dose can be repeated several times and increased to 0.3 mg/kg if needed. This is possible because of its short half-life, which precludes toxic side effects from drug accumulation.
REFERENCES 1. Ludomirsky A, 6arson A: Supraventrieular tachycardia, in 6illette PC, Garson A (eds): Pediatric Arrhythmias: Electrophysiology and Pacing, ed 1. Philadelphia, WB Sa unders, 1990, p 380-426. 2. Drury AN, Szent-6yorgyi A: The physiological activity of adenosine compounds with especial reference te their action upon the mammalian heart. J Physio11929;68:213-237. 3. West 6A: Actions of adenosine on the sinus node. Prog Clin BiolRes 1987;230:97-108. 4. Belardinelli L: Modulation of atrioventricular transmission by adenosine. Prog Clin Biol Res 1987;230:109-118. 5. DiMarco JP: Adenosine and supraventricular tachycardia. Prog Clin Biol Res 1987;230:271-282. 6. Moak JP: Pharmacology and electrcphysiology of antiarrhythmic drugs, in Gillette PC, Garscn A (eds): Pediatric Arrhythmias: Electrophysiology and Pacing, ed 1. Philadelphia, WB Saunders, 1990, p 37-117.
SUMMARY
Adenosine should be considered the first drug of choice in the treatment of PSVT in infants and children. Adenosine should also be considered in patients who are hemodynamically unstable, because of its fast onset of action. However, controlled, prospective studies should be performed to establish the true efficacy and safety of adenosine in the treatment of PSVT in the pediatric population as compared with digitalis, verapamil, and propanolol.
7. DiMarco JP, Sellers TD, Lerman BB, et al: Diagnostic and therapeutic use of adenosine in patients with supraventricular tachyarrhythmias. JAm Coil Cardiol 1985;8:417-425. 8. Clarke B, Till J, Roland E, et al: Rapid and safe termination of supraventricular tachycardia in children by adenosine. Lancet 1987;1:299-301. 9. Ros SP, Fisher EA, Bell TJ: Adenosine in the emergency treatment of supraventricular tachycardia. Pediatr Emerg Care 1991;7:222-223. 10. Till JA, Shinebourne EA: Supraventricular tachycardia: Diagnosis and current acute management. Arch Dis Child 1991;66:647-652. 11. Overholt ED, Rheuban KS, 6utgesell HP, et al: Usefulness of adenosine for arrhythmias in infants and children. Am J Cardio11988;61:336-340. Address for reprints: Antonio G Galvis, MD Childrens Hospital Los Angeles Division of Pediatric Intensive Care 4650 Sunset Boulevard Los Angeles, California 90027
DECEMBER1992
21:12
ANNALS OF EMERGENCY MEDICINE
1501/I21
